1. Field of the Invention
The present invention relates to a composite switch unit for vehicle use for changing over various vehicle-mounted functions, and more particularly to a composite switch unit positioned in the vicinity of the steering wheel.
2. Description of the Prior Art
To explain drawings of a composite switch unit for vehicle use according to the prior art, FIG. 4 shows a schematic exploded perspective view of the prior art composite switch unit for vehicle use; FIG. 5, a schematic section of the essential part of the prior art composite switch unit for vehicle; FIG. 6, a vertical section of one side of the essential part of the prior art composite switch unit for vehicle use; and FIG. 7, a horizontal section of the same side of the essential part of the prior art composite switch unit for vehicle use of FIG. 6.
Next to describe the configuration of the prior art composite switch unit for vehicle use, as shown in the schematic diagrams of FIG. 4 and FIG. 5, a casing 50 is an insulating resin body having a relatively large overall length and an inverted U shape. In the right and left walls and the ceiling are provided guide grooves 50a, and the ceiling also has a central hole 50b near the center of the top face of the casing 50. Around the central hole 50b, on the top face of the casing 50 are provided a plurality of guide stubs 50c, and between the guide stubs 50c and the central hole 50b are bored holes 50d. 
A rotary connector 53 consists of an insulating resin-made cylindrical fixed body 53a and an insulating resin-made movable body 53b rotatably fitted to the fixed body 53a and having a cylindrical hole 53i, and a flat cable 53h is wound in the cylindrical space demarcated by these fixed body 53a and movable body 53b to electrically connect the fixed body 53a and the movable body 53b. The under face of the fixed body 53a and the top face of the movable body 53b are provided with a connector 53c and a connector 53d, respectively, for electrical connection to the outside. On the upper edge of the cylindrical outer wall of the fixed body 53a are provided a plurality of protrusions 53f protruding in the horizontal direction, and the plurality of protrusions 53f have a plurality of holes 53e. The plurality of protrusions 53f are guided by the plurality of guide stubs 50c of the casing 50, and bolts 53g penetrate the holes 53e and the holes 50d to fix the fixed body 53a to the periphery of the central hole 50b of the casing 50.
A winker side stalk switch 51 which is on one side of the composite switch unit for vehicle use, as schematically illustrated in FIG. 4 and FIG. 5, has an insulating resin-made, rod-shaped lever 51a and a box-shaped base body 60 to which this lever 51a is fitted. On the surrounding edge of the base body 60, a connector 51c is provided on the other face than that to which a plurality of guide stubs 51b and the lever 51a of the base body 60 are fitted.
To describe the base body 60 with reference to FIG. 6 and FIG. 7, an upper case 60a and a lower case 60b, both made of insulating resin, protect the base body 60 by covering it from above and underneath, and have opposite shaft holes. A thin and long working member 60c, made of insulating resin, is fixed to the lever 51a to communicate the oscillating motion of the lever 51a and invades into the base body 60, and a long hole 60f opens in the invading direction. A holder 60e, an insulating resin-made structure, is accommodated between the upper and lower cases 60a and 60b, and has two shafts (not shown) protruding in the horizontal direction and another pair of protruding shafts 60j and 60k protruding in the vertical direction. The holder 60e also has a spring shoe 60m inside. Protruding shafts of the holder 60e are snapped into shaft holes 60d of the working member 60c to make the lever 51a fixed to the working member 60c oscillatable in the directions of arrow a-b. The protruding shafts 60j and 60k of the holder 60e are snapped into opposite shaft holes of the upper and lower cases 60a and 60b, and the holder 60e is oscillatable relative to the upper and lower cases 60a and 60b in the directions of arrow c-d of the lever 51a. 
An insulating resin-made cap 60h, whose tip is formed hemispherically, is snapped onto the tip of a first coil spring 60g. The first coil spring 60g to which the cap 60h is fitted is accommodated in the hole 60f of the working member. A first cam wheel assembly 60i has one or more insulating resin-made cam wheels, and is formed in a position in a part of the holder 60e, opposite the hole 60f of the working member 60c. The cap 60h is elastically suppressed as an elastic suppressing portion against the first cam wheel assembly by the elastic force of the first coil spring 60g. 
An insulating resin-made cap 60n, whose tip is formed hemispherically, is snapped onto the tip of a second coil spring 60l. The second coil spring 60l to which the cap 60n is fitted is borne by the spring shoe 60m provided on the holder 60e. A second cam wheel assembly 60o has two insulating resin-made cam wheels 60q and a central trough 60p between them, and is integrated with the lower case 60b. The cam wheel faces are provided opposite the cap 60n snapped onto the tip of the second coil spring. The cap 60n is elastically suppressed as an elastic suppressing portion against the second cam wheel assembly 60o by the elastic force of the coil spring 60l. 
A contact change-over member 60s has a hole 60w in its insulating resin-made body, to which a movable contact 60v is fitted. A protrusion 60w protruding from the working member 60c is inserted into the hole of the contact change-over member 60s, and the movable contact 60v moves with the oscillation of the lever 51a fixed to the working member 60c in the directions of arrow a-b. Another contact change-over member 60t has a protrusion and a movable contact 60u in its insulating resin-made body, whose protrusion is in contact with and squeezed by a wall 60x of the holder 60e, and the movable contact 60u is moved as the wall 60x is interlocked with the oscillation of the lever 51a in the directions of arrow c-d.
A printed circuit board 60r is fitted to the lower case 60b, and on its surface is provided switchable contacts (not shown) for changing over various functions of the vehicle. To an end of the printed circuit board 60r is fitted a connector 51c to guide outside the signals of the switchable contacts via a connecting conductor 51d of the connector 51c. The winker side stalk switch 51, which changes over from one contact to another by having the contact change-over members 60s and 60t slide over and in contact with the switchable contacts, is snapped on and fixed to the casing 50 by inserting the plurality of guide stubs 51b on the peripheral edge of its base body 60 into the guide grooves 50a in the right and left inner walls and the ceiling of the casing 50.
A window wiper side stalk switch 52, which is on the other side of the composite switch unit for vehicle use is substantially the same in structure as the winker side stalk switch, and therefore its detailed description will be dispensed with.
The window wiper side stalk switch 52 is snapped on and fixed to the casing 50 by inserting the plurality of guide stubs 52b on the peripheral edge of its base body 61 into the guide grooves 50a in the right and left inner walls and the ceiling of the casing 50.
A rectangularly shaped relaying printed circuit board 54 has a hole 54a at the center, is mounted with a connector 54b, a connector 54c and a connector 54d. From these three connectors, wiring is laid via leads (not shown) on the printed circuit board 54, and these leads are gathered on the back face of the printed circuit board 54 via through holes to be concentrated on another connector 54e mounted on the back face of the printed circuit board thereby to relay signals to the vehicle per se.
The relaying printed circuit board 54 is fitted and fixed to the lower edge of the casing 50. If, when it is fitted, the rotary connector 53 is caused to be guided by the plurality of guide stubs 50c to be inserted into the hole 50b of the casing 50, the connector 53c on the lower edge of the rotary connector 53 is snapped on and connected to the connector 54b mounted on the relaying printed circuit board 54. Then, as the plurality of guide stubs 51b of the winker side stalk switch 51 are inserted into the guide grooves 50a of the casing 50 in the direction reverse to the lever 51a and snapped on for fixation, the connector 51c provided on the base body 60 of the winker side stalk switch 51 on the other face than where the lever 51a is fitted is snapped on and connected to the connector 54d fitted to the relaying printed circuit board 54.
When the window wiper side stalk switch 52 is snapped on and fixed by inserting its plurality of guide stubs 52b into the guide grooves 50a of the casing 50, a connector 52c (though not shown, it is for an output from an printed circuit board inside like that for the winker side stalk switch 51) provided on the face of the base body 61 of the window wiper side stalk switch 52 reverse to where a lever 52a is fitted is snapped on and connected to the connector 54c fitted to the relaying printed circuit board 54. The cylindrical hole 53i of the movable body 53b of the rotary connector 53 and the central hole 54a of the relaying printed circuit board 54 are formed concentrically, and a steering shaft is pressed into them after final assembly.
Next will be described the oscillating action of the lever 51a of the winker side stalk switch 51 and the resultant driving of the contact change-over members 60s and 60t. As shown in FIG. 6, when the lever 51a is oscillated in the directions of arrow a-b pivoting on the shaft hole 60d provided in the working member 60c fixed to the lever 51a, as the insulating resin-made cap 60h snapped onto the tip of the first coil spring 60g is elastically suppressed by the first cam wheel assembly 60i formed in part of the holder 60e, the motion of the cap 60h to go over a cam wheel gives the lever 51a a feel of click and causes the lever 51a to be latched into a prescribed position. At the same time, as the protrusion 60w protruding from the working member 60c fixed to the lever 51a engages with a hole in the contact change-over member 60s along with the oscillation of the lever 51a to drive the contact change-over member 60s, the movable contact 60v of the contact change-over member 60s slides over, keeping contact with, the opposite printed circuit board 60r to give a high beam signal to turn on a high beam lamp (not shown).
When the lever 51a is oscillated in the directions of arrow c-d around the protruding shafts 60j and 60k at the ends of the holder 60e, the insulating resin-made cap 60n snapped onto the tip of the thin and long second coil spring 60l, as it is elastically suppressed by the second cam wheel assembly 60o integrated with the lower case 60b, gives a feel of click to the lever 51 and latches the lever 51a in a prescribed position when it goes over the cam wheel 60q. At the same time, the wall 60x of the holder 60e, moving integrally with the lever 51a, drives the protrusion of the contact change-over member 60t in contact with that wall along with the oscillation of the lever 51a, the movable contact 60u slides over, keeping contact with, the opposite printed circuit board 60r, and is driven by the rotational operation of the lever 51a to turn right of left and thereby to light the right turning or left turning lamp (not shown) intermittently.
As described the feel of click resulting from the oscillation of the lever 51a in the directions of arrow a-b is created by the cap 60h and the cam wheel assembly 60i, the feel of click resulting from the oscillation of the lever 51a in the directions of arrow c-d is created by the cap 60n and the cam wheel assembly 60o. This use of different caps different cam wheels for the two purposes complicates the structure.
Since the oscillating action of the lever 52a of the window wiper side stalk switch 52 is substantially the same as that of the lever 51a of the winker side stalk switch 51, its detailed description will be dispensed with, but it may be sufficient to note here that the functions changed over by the oscillation action of the lever 52a of the window wiper side stalk switch 52 are speed control of the window wipers and the discharge of the window washer liquid.
According to the prior art described above, each stalk switch is provided with a printed circuit board, which then is provided with connectors, which in turn are connected to a relaying printed circuit board. This configuration according to the prior art requires a plurality of printed circuit boards and accordingly involves greater trouble of assembling and, moreover, the use of connectors between each stalk switch and the relaying printed circuit board entails the problem of inadequate reliability of electrical connection.
Therefore, an object of the present invention is to provide a composite switch unit for vehicle use using a smaller number of printed circuit boards, easier to assemble and more reliable in electrical connection.
In order to solve the problems noted above, a composite switch unit for vehicle use according to the invention is provided with a plurality of switchable contacts on a relaying printed circuit board for centralized relaying of signals between a vehicle per se and the switch unit, wherein a plurality of contact change-over members for connecting and disconnecting the switchable contacts are mounted on the printed circuit board; a drive member oscillatable from outside to inside of a box-shaped housing is fitted to each end of the housing in a lengthwise direction; the printed circuit board is fixed to an outer part of an under face of the housing to cause the contact change-over members to face the inside of the housing; the drive members and the contact change-over members are engaged with each other to oscillate the drive members; and the contact change-over members are thereby driven to change over the switchable contacts on the printed circuit board.
This configuration makes it possible to provide a composite switch unit for vehicle use reduced in the number of printed circuit boards to be used, easier to assemble and increased in the reliability of electrical connection.
In the composite switch unit for vehicle use according to the invention, each of the drive members may include a lever assembly protruding outside the housing, an oscillating body provided within the housing and a cam wheel assembly; the cam wheel assembly has a cam wheel whose elastically suppressed portion protruding to an inner end of the lever assembly is suppressed; the lever assembly is given a feel of click matching an oscillating position of the lever assembly; and the cam wheel assembly is fitted detachably to the housing.
This configuration makes it easier to change the feel of click because it can be changed by replacing only the cam wheel assembly with a differently prepared one.
In the composite switch unit for vehicle use according to the invention, the lever assembly may be borne by the oscillating body to be oscillatable in fixed directions; and the oscillating body is borne by the housing in directions substantially orthogonal to the fixed directions.
This configuration makes possible oscillation in two directions in a simple structure.
In the composite switch unit for vehicle use according to the invention, one of the elastically suppressed portions may be provided for one unit of the lever assembly, and the elastically suppressed portion is suppressed by the cam wheel to move in mutually orthogonal directions over the cam wheel.
As this configuration requires only one elastically suppressed portion, the overall structure of the composite switch unit for vehicle use is simplified.
The composite switch unit for vehicle use according to the invention may have a cover for covering the relaying printed circuit board jointly with the housing.
Since in this configuration the relaying printed circuit board is covered by both the housing and the cover, the relaying printed circuit board can be protected from dust.
In the composite switch unit for vehicle use according to the invention, the relaying printed circuit board may be provided with lead conductors for collectively leading signals of the plurality of switchable contacts toward the vehicle per se.
This configuration can accomplish connection of signals to the vehicle per se simply with a connector using lead conductors.